Where should bulking agents for female urodynamic stress incontinence be injected?

Abstract

For bulking agents used for female stress urinary incontinence, the recommendation for the anatomical placement varies as some injectables are to be placed close to the bladder neck and others midurethrally. Aim of the study was to determine if there are differences concerning the outcome after transurethral collagen injections depending on the anatomical placement midurethrally or at the bladder neck. We randomly assigned 30 elderly female patients with urodynamic stress incontinence to either transurethral collagen injection midurethrally or to the bladder neck. Prior to injection and at ten month follow-up, maximum urethral closure pressure (MUCP), functional urethral length (FUL), maximum flow rate and cough test were performed and the patient was asked to estimate her bladder condition using a visual analogue scale. Postoperative contentness was 8 (median, 95% confidence interval 5-9) in the midurethral group and 8 (median, 95% confidence interval 7-10) in the bladder neck group with a p value of 0.012, 95% confidence interval -2.464 to -0.2859, in favour to midurethral injections. MUCP and FUL increased significantly in both groups and flow rate decreased in both groups. Continence was 66.6% in the midurethral group and 60% for the bladder neck group respectively. Both midurethral and bladder neck collagen injections improve patients' satisfaction almost equally with a small advantage for midurethral injections.

Bulking agents: an analysis of 500 cases and review of the literature

“…Endoscopic delivery of bulking agents under local anesthesia is typical, yet a blind administration via special devices may be considered beneficial [28]. The appropriate site for injection is the midurethra [29], and the mode of delivery of the agent (periurethral vs. transurethral) leads to similar outcomes but increased early complications if administered periurethrally [10]. Two or three injections are likely to be required to achieve a satisfactory result [10].…”

An open multicenter study of polyacrylamide hydrogel (Bulkamid®) for female stress and mixed urinary incontinence

“…In this study, the material was injected in the upper third of the urethra, but a recent study seems to indicate that the bulking effect can be improved by injecting into the mid urethral zone [34]. …”

Urethral bulking agents: Techniques and outcomes

“…Kuhn et al [5] found that the injection of bulking agents at the bladder neck and midurethra almost equally improved patient satisfaction, with a small advantage for midurethral injection. The "integral theory" of Petros and Ulmsten [6] supports the argument that midurethral injection is more effective in patients with associated urethral hypermobility because it provides urethral stabilization.…”